**In case where the selling price of two articles is the same and one is sold at a loss of X% and another is sold at a profit of X% then this will always leads to a loss of X^2/100 %**

A shopkeeper sells two books at the same price. If he sells one book at a profit of 30% and another book at a loss of 30%, find the profit or loss percentage

A.9% profit

B.9% loss

C.No profit no loss

D.cannot be determined

Answer: (30)^2/100 %

900/100 %

9% loss

Logic: First articles is sold @30% profit that is 130/-. Therefore the SP will be 130 /-.

Now since both articles are sold at a same price, the SP of another articles will be 130/-.

Now another articles will be sold @ 30% loss that is Rs.39 that is at Rs.91.

Therefore the loss is 100-91 = 9

= 9/100 = 9%

Note: 1) Both Percentage should be same to solve this problem

2) One must be sold at a profit and another at a loss. (order does not matter)

3) It always lead to loss only

WHY?**Suppose the SP is 100**

First sold at a profit of 10% and then loss at a loss of 10% then it will result in final price of 100+10% of 100 = 110

110 - 10% of 110= 99

**So final loss would be 100-99 = 1**

Now. change the order and first sold at loss and then sold at profit that is

100-10% of 100= 90

90 + 10% of 90 = 99

**so final loss would be 1**So there would be loss in both case...l